Python: Find the Nth member of the sequence

Python Basic - 1: Exercise-22 with Solution

Nth Member of Sequence

Write a Python program to create a sequence where the first four members of the sequence are equal to one. Each successive term of the sequence is equal to the sum of the four previous ones. Find the Nth member of the sequence.

Sample Solution:

Python Code:

# Define a recursive function 'new_seq' that generates a new sequence based on the sum
# of the four previous terms. The base cases are when 'n' is 1, 2, 3, or 4, where the
# function returns 1.
def new_seq(n):
    if n == 1 or n == 2 or n == 3 or n == 4:
        return 1
    
    # Recursive step: The function returns the sum of the four previous terms.
    return new_seq(n - 1) + new_seq(n - 2) + new_seq(n - 3) + new_seq(n - 4)

# Test the 'new_seq' function with different values of 'n' and print the results.
print(new_seq(5))
print(new_seq(6))
print(new_seq(7))

Sample Output:

4
7
13

Explanation:

This Python code defines a recursive function named "new_seq()" that generates a sequence based on the sum of the four previous terms. Here's a brief explanation:

• Function Definition:
• def new_seq(n):: Define a recursive function named "new_seq()" that takes an integer 'n' as input.
• Base Cases:
• if n 1 or n 2 or n 3 or n 4:: Check if 'n' is 1, 2, 3, or 4.
• return 1: If 'n' is one of these values, return 1 as a base case.
• Recursive Step:
• return new_seq(n - 1) + new_seq(n - 2) + new_seq(n - 3) + new_seq(n - 4): If 'n' is greater than 4, calculate the sum of the four previous terms using recursive calls to the "new_seq()" function.
• Function Testing:
• print(new_seq(5)): Test the function with 'n' equal to 5 and print the result.
• print(new_seq(6)): Test the function with 'n' equal to 6 and print the result.
• print(new_seq(7)): Test the function with 'n' equal to 7 and print the result.

Flowchart:

Python Code Editor:

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